Ataxia Telangiectasia
Ataxia Telangiectasia: Ataxia Telangiectasia, also known as A-T, is a rare genetic disorder presented during childhood. People are generally diagnosised with this genetic disorder at the age of five, but can be diagnosised later on in life as well. A-T affects the nervous system, immune system, and other body systems. The disorder causes degeneration in the part of the brain that controls motor movements and speech along with the breakdown of the immune system. The breakdown of the immune system leaves the patient susceptiable to diseases, one of which is cancer. Patients diagnosised with A-T are wheel chair bound by their teens, and the disease is generally fatal in the early twenties. Symptoms: *Delayed development of motor skills and speech *poor balance *slurred speech *acute sensitivity to ionizing radiation (x-rays and gamma rays) *involuntary jerking movements *muscle twitches *Telangiectasias, web red-like veins, appear at the corners of the eyes, cheeks and ears (not always a symptom to the diease) Diagnosis: A-T is diagnosised clincally through examination and identification of the ataxia or the skin telangiectasia. This is followed by lab tests for serum AFP level, the response of white blood cells to X-rays and measurement of the level of ATM protein. Patients with A-T may have a low lymphocyte count and the other immunological abnormalities. Molecular testing can follow this procedure to confirm the diagnosis. This is carried out by the seqeuncing all 66 exon of the gene or by the linkage of the family history. MRI and CT scans may show signs of cerebellar atrophy. Prognosis: One in four hundred thousand people are affected worldwide. One percent, or two point five million, people in the United States are affected in the United States.Twenty percent of those diagnosed with A-T develop cancer, either lymphoctic leukemia or lymphoma. Death is more prevelant in the early teens and early twenties. Frequency: A-T is reported in all the regions of the world. The frequency of the mutant allele is said to be 1.4-2% of the general population. THe genetic disorder is reported in all races, although mortality rates do differ between the races. A-T is also not dependent on the sex of the patient. It occurs equally in both males and females. Cause: A-T is due to a mutation on the ATM gene. This gene provides instructions for making a protein that helps control cell division, and is also involved in DNA repair. The protein plays an important role in the development and activity of several body systems, including the nervous system and immune system. Mutation on the ATM gene reduce or eliminate the function of the ATM protein. Without this protein, cells become unstable and can die quickly, which mainly affects the cells in the cerebellum (the part of the brain that controls movements). THe loss of these brain cells cause the movement problems involved with the genetic disorder. Mutations in the ATM gene also prevent cells from responding correctly to DNA damage, which allows breaks in DNA strands to accumulate and can lead to the formation of cancerous tumors. Methods of Inheritance: A-T is an inherited autosomal recessive pattern that allows both copies of the ATM gene in each cell to have mutations. Most otften, the parents of an individual with an autosomal recessive condtion can carry one copy of gene, but not show any signs or symptoms of the disorder. About one percent of the United States population carries one mutated copy and one normal copy of the ATM gene in each cell. Carriers of a mutation in the ATM gene can develop breast cancer and have a high risk of heart disease and diabetes. Treatments: There is no cure for A-T yet. Cloning and sequening of the ATM gene has opened several avenues of research to develop better treatmnent, including gene therapy, designs of new drugs to correc the function of the alternated protein, and direct replacement of the functional protein. Physical, occupational, and speech therapy are used to help maintain flexibility. Gamma-globulin injections help supplement the immune systems of A-T patients. Also, a high dose vitamin regimens are being researched with some moderate results. In addition to these methods, the A-T Children's project is a non-profit organization that raises funds to support and coordinate biomedical research projects to find a cure for A-T. Sources: http://emedicine.medscape.com/article/1113394-overview http://www.cancer.gov/cancertopics/factsheet/risk/ataxia http://ghr.nlm.nih.gov/condition/ataxia-telangiectasia http://www.featmovie.com/whatis.html